Weld beveling of large-diameter pipes

Technique employs electric drill and newly developed special jig to J-bevel, in the field, ends of pipes measuring between 15.24 cm and 45.72 cm in diameter in preparation for welding. Jig's construction and operation are described

Determining Cosserat constants of 2D cellular solids from beam models

We present results of a two-scale model of disordered cellular materials where we describe the microstructure in an idealized manner using a beam network model and then make a transition to a Cosserat-type continuum model describing the same material on the macroscopic scale. In such scale transitions, normally either bottom-up homogenization approaches or top-down reverse modelling strategies are used in order to match the macro-scale Cosserat continuum to the micro-scale beam network. Here we use a different approach that is based on an energetically consistent continuization scheme that uses data from the beam network model in order to determine continuous stress and strain variables in a set of control volumes defined on the scale of the individual microstructure elements (cells) in such a manner that they form a continuous tessellation of the material domain. Stresses and strains are determined independently in all control volumes, and constitutive parameters are obtained from the ensemble of control volume data using a least-square error criterion. We show that this approach yields material parameters that are for regular honeycomb structures in close agreement with analytical results. For strongly disordered cellular structures, the thus parametrized Cosserat continuum produces results that reproduce the behavior of the micro-scale beam models both in view of the observed strain patterns and in view of the macroscopic response, including its size dependence

How economic crisis is affecting firms? Building resilience capacity through innovation

More than ever firms will be required to develop strategies for coping with future shocks and stresses to our economic and social infrastructures. They will need to build the so called resilience capacity, which is an umbrella term for the planning and design strategies that help firms to develop the necessary capacity to meet challenges. The present paper, based on an assessment of works that explore recent European reports on innovation performance, discusses some underling effects of the economic crisis. This discussion reveals the main differentiating impacts of a major downturn on innovation behavior. Some of the conclusions acknowledge that firms will have to find new ways to reduce their risk-averse dependency and become more flexible. To become more resilient, firms will need to adopt planning and design strategies that allow them to develop the capacities to better respond and adapt to the emerging economic and social stresses. Developing these capacities will involve firms in a complex web of planning and development decisions that, in combination, must be designed to transform our current economic systems into much more flexible and dynamic ones. Small and medium enterprises are more exposed to high competitive pressures. Thus, they have to search for new business opportunities. The choice of sectors and the design of public procurement policies can provide new opportunities and it is very likely that those that manage to capture them will be the winners. With the polarization of innovation and knowledge creation across Europe, a few countries are responsible for the bulk of innovation and knowledge production. The technology gap provides a fundamental potentiality for lagging behind countries to catch-up. However, there is a general fragility as major effects of the crisis have shown. Therefore, a more articulated policy needs to be put in practice as suggested and more attention should be given to investment in knowledge diffusion and absorption depending on the specific national context. The fact that some structural characteristics of the national innovation system explain persistency of innovation in response to major exogenous shocks sheds some light on the behavior of firms during crisis. This represents a step forward in terms of understanding the mechanisms underlying the relationship between macro and micro-determinants of innovation

Tax evasion and exchange equity: a reference-dependent approach

The standard portfolio model of tax evasion with a public good produces the perverse conclusion that when taxpayers perceive the public good to be under-/overprovided, an increase in the tax rate increases/decreases evasion. The author treats taxpayers as thinking in terms of gains and losses relative to an endogenous reference level, which reflects perceived exchange equity between the value of taxes paid and the value of public goods supplied. With these alternative behavioral assumptions, the author overturns the aforementioned result in a direction consistent with the empirical evidence. The author also finds a role for relative income in determining individual responses to a change in the marginal rate of tax

New Insights into the Control of Cell Fate Choices and Differentiation by Retinoic Acid in Cranial, Axial and Caudal Structures

Retinoic acid (RA) signaling is an important regulator of chordate development. RA binds to nuclear RA receptors that control the transcriptional activity of target genes. Controlled local degradation of RA by enzymes of the Cyp26a gene family contributes to the establishment of transient RA signaling gradients that control patterning, cell fate decisions and differentiation. Several steps in the lineage leading to the induction and differentiation of neuromesodermal progenitors and bone-producing osteogenic cells are controlled by RA. Changes to RA signaling activity have effects on the formation of the bones of the skull, the vertebrae and the development of teeth and regeneration of fin rays in fish. This review focuses on recent advances in these areas, with predominant emphasis on zebrafish, and highlights previously unknown roles for RA signaling in developmental processes